The Long-term goal of this research is to develop novel dentifrice formulations containing bioactive glasses that will replace or be an adjuvant to fluoride as an anti-cares agent. The initial focus of the research will be to develop reduced fluoride formulations which have equivalent or superior anti-caries efficacy to commercially available formulation. These formulations will be beneficial to the general population and to segments of the population where the potential benefits of using a standard fluoride dentifrice formulation is reduced. Bioactive glasses have been successfully used clinically as a bone grafting material for over fifteen years. Recently it has been documented that fine particulate bioactive glasses incorporated into an aqueous dentifrice have demonstrated an ability to clinically reduce tooth hypersensitivity through the occlusion of dentinal tubules. In vitro studies have demonstrated significant occlusions and remineralization of prepared bovine dentin and remineralization of precarious surface lesions. Other in vitro studies have demonstrated significant anti-microbial effect towards caries pathogens. The Specific Aims of this Phase I application are to: 1) test single phase anhydrous and dual phase aqueous dentifrice formulations to characterize their efficacy, 2) conduct accelerated stability testing of the most promising formulations, 3) test selected formulations from Aim 2 for anti-microbial activity and, 4) evaluate them using established in vitro subsurface caries models to predict in vivo efficacy.